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Thermo-Insulation Properties Of Hemp-Based Products

Authors:
  • Latvia University of Life Sciences and Technologies, Ulbroka research centre

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As known, many multi-purpose plants can be used in different industries. This research is focused on the possibilities to utilize hemp as feedstock for thermal insulation products. The most advantageous features of hemp insulation are associated with health and environmental safety. The thermal conductivity of commercially available hemp insulation products is comparable with that of other fibrous insulation materials; however, it is possible to develop new products that could be more efficient in terms of cost and due to other important features.
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LATVIAN JOURNAL OF PHYSICS AND TECHNICAL SCIENCES
2015, 1
DOI: 10.1515/lpts-2015-0004
THERMO-INSULATION PROPERTIES OF HEMP-BASED PRODUCTS
V. Lekavicius1, P. Shipkovs1, S. Ivanovs2, A. Rucins2
1 Institute of Physical Energetics,
21 Aizkraukles Str., Riga, LV-1006, LATVIA
2 Agency of Latvia University of Agriculture Research
Institute of Agricultural Machinery,
1 Instituta Str., Ulbroka, Stopinu nov., LV-2130, LATVIA
As known, many multi-purpose plants can be used in different indus-
tries. This research is focused on the possibilities to utilize hemp as feedstock
for thermal insulation products. The most advantageous features of hemp
insulation are associated with health and environmental safety. The thermal
conductivity of commercially available hemp insulation products is compa-
rable with that of other brous insulation materials; however, it is possible to
develop new products that could be more efcient in terms of cost and due to
other important features.
Keywords: hemp thermal insulation, thermal conductivity, thermal in-
sulation materials.
1. INTRODUCTION
Rapid changes in the energy prices and incessant debates on climate change
impose increasing requirements on the energy efciency. The power consumption
for heating and cooling of buildings makes up a considerable share of the total en-
ergy consumption in Europe. Therefore, requirements for insulation of buildings,
and, consequently, demand for insulation materials are growing. Particularly strong
trend exists towards natural and environment-friendly insulation materials. One of
the natural local resources for production of insulation materials is hemp (Cannabis
sativa L.). The purpose of this research is to analyze the context and specic features
of hemp-based thermal insulation products.
Currently, insulation materials produced from hemp make up only a small
share in the European market for thermal insulation products. According to the IAL
Consultants data, the total market for thermal insulation products in Europe reached
approximately 193 million m3 in 2012, whereas the value of this market was esti-
mated at 9.6 billion euro [1]. The share of hemp insulation materials in this market
can be considered as very small in terms of physical volume and value (both much
less than 1% of the total market size). However, hemp insulation materials are of
considerable promise for the future if we take into account increasing environmental
awareness of people.
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2. HEMP IN EUROPE: GROWING AND UTILIZATION
Although the climatic conditions are suitable for hemp bre growing almost
in the whole Europe, considerable amounts of hemp are traditionally grown only in
several countries. This is also connected with legal issues: in some countries grow-
ing hemps of denite type is forbidden due to possible use as a drug substance.
The top producers of hemp straw in Europe are France (42.7 thousand tons
in 2011), Germany, United Kingdom, and the Netherlands. The actual numbers are
varying considerably from year to year, depending on the realization opportunities
and other factors. Even in France, the land area used for hemp was only 5400 ha in
2011, while in 2009 this area was 11300 ha [2]. Such a lack of steady trend gives
a ground for arguing that hemp is a niche product that is highly dependent on the
market conjuncture and other external factors. Furthermore, the changes in hemp
cultivation area show that in European countries there are no strict constraints on the
area for hemp production. The ows of hemp straw are depicted in Fig. 1.
Fig. 1. Production and utilization of hemp straw in the European Union [2], [3].
Particular parts of hemp straw can be utilized in various ways. Although the
proportions in Fig. 1 are not xed on this aspect, this picture illustrates a usual prac-
tice in 2010 and shows the potential for different hemp straw utilization.
According to the data from the European Industrial Hemp Association, insu-
lation materials occupy one of the most important utilization areas of hemp bres: in
2010, 25.9% hemp bres were used in production of insulation materials. Moreover,
15% hemp chaffs were utilized in the construction industry, mainly for production of
the so-called hempcrete [3]. This substance can be dened as a lightweight insulat-
ing and breathable material produced by mixing hemp chaffs with a lime base binder
and water. As compared with conventional concrete, such a mixture has different
mechanical and acoustic properties [4]. The empirical tests show that the addition of
some amount of hemp to a mortar improves the thermal performance of the material
and makes it lighter [5]. Hempcrete can be used for insulation quilts, oors, roofs,
screeds, mortars or insulation plasters which can be either cast or sprayed. Hemp
chaffs can also be used for producing hemp bricks based on the principle similar to
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that for hempcrete production [4]. Hemp chaffs may be utilized in biodegradable
boards for different lightweight constructions, such as mobile homes, packing mate-
rial, etc. [6]. It should be noted that the quantitative relationship between bres and
chaffs is here more or less stable. Therefore, if the market for one of these materials
(e.g. bres) is expanding, the supply of the other one is also increasing. Thus, it is
expected that hemp chaffs have a big potential for improving the construction busi-
ness in terms of sustainability [7].
Another potential hemp utilization area is fuel for direct burning or feedstock
for pellet production. The most important properties of some biomass fuels are com-
pared in Table 1.
Table 1
Caloric Values of Biomass Fuels [8]
Material Caloric value (MJ/kg) Assumed
Moisture content (%)
Gross Net
Hemp 18.5 13.4 20
Wood residues 19.7 10 40
Straw 18 13 20
Peat 21.5 8.9 50
Although the hemp pellet production for domestic use can be limited, big boil-
ers for industrial heating or power generation are seen as a promising option of hemp
utilization. One of the most attractive advantages of hemp is that it can be eld-dried
to 20% moisture. In this case, its net caloric value (the heat available with no fur-
ther drying and no recovery of latent heat) is higher than that of many other forms of
biomass and much higher than that of peat [8].
To sum up, approximately 16.5% of hemp straw is currently used in the con-
struction sector as insulation or building material. As to the potential applications, it
might be good if the part of hemp chaffs currently used as bedding material could be
utilized in construction or consumed as fuel. This makes hemp a true energy plant,
with the potential of being both energy conservation material and energy resource.
Moreover, in both the usage directions, hemp has a true potential for reducing green-
house gas emissions.
3. THE FEATURES OF HEMP INSULATING MATERIALS
The features of insulating materials are traditionally classied into three main
groups: physical, environmental and health-related [9].
The rst group of features deals with the traditional physical parameters – i.e.
density, thermal conductivity, sound absorption – that can be measured using stand-
ard procedures.
The measurement of parameters belonging to the second group is much more
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complicated, since the evaluation of life-cycle environmental impacts depends on
many assumption-based factors, and sometimes might be subjective. Possible im-
pact on the climate change is also accounted for among environmental features, a
good case in this important point being the ozone depletion potential of chemical
materials, such as chlorouorocarbons and hydrochlorouorocarbons that are emit-
ted during the life cycle of some foam-type insulation materials (e.g., extruded pol-
ystyrene, polyisocyanurate) [10]. A more comprehensive approach to the environ-
mental issues also includes the use of primary energy in the process of insulating
material production as was the case in the model integrated of life-cycle costing
and dynamic thermal simulation (MILD). The application of this model for a sheep
farm in the Italian Apennines has shown that the best performances are obtained for
glass wool, sheep wool and hemp bre. If the criterion of primary energy input cost
is eliminated, the polyurethane passes from the least to the most preferable material
[11]. Thus, inclusion of environmental criteria highlights the advantages of hemp
and other natural insulation materials over synthetic ones.
Similarly to the second group, the third one deals with the issues that might
appear at any stage of the life cycle of a material, but in practice the main attention
is paid to the dust emissions and toxicity during the installation and use of mate-
rial, a good illustration being glass wool that might cause health-related problems
such as respiratory diseases to the personnel involved in the installation works.
Health-related features can depend not directly on the insulation material itself,
but also on the suitable conditions for the usage of a particular insulation material.
Sometimes there is a need to perform careful calculations in order to ensure good
microclimate in the building and avoid mould that might be a cause of many medi-
cal disorders.
In addition to these groups of features, economic characteristics, such as the
price of insulating material itself or the cost of installation, must also be mentioned
as important for insulating materials.
The above-mentioned groups are usually closely interrelated: poor hygric
properties may result in deterioration of thermal insulation ability and mould prolif-
eration; the use of toxic materials in the production process causes both environmen-
tal and health problems, etc.
In practice, the actual choice of insulating material for a building depends also
on other objective and subjective factors related to its peculiarities, the existing (or
foreseen) heating (cooling) system, and the consumer’s preferences considering the
importance of each element in above mentioned groups of features. The decision
made is usually a result of considerations that are based on many factors associated
with specic weights that express the importance of each factor. In some cases, high-
ly-skilled experts and quite complex multiple-criterial decision making methods are
employed in order to choose the most suitable material [12].
The characteristics of a particular thermal insulation product may depend on
many factors, including its composition, quality of feedstock, technology that is used
for its production, etc. A brief description of some hemp insulation materials that are
currently available in the market is provided in Table 2.
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Table 2
Properties of Hemp Thermal Insulation Products Available in the Market
Thermo-Insu-
lation product Composition
Thermal
Conduc-
tivity,
W/(m∙K)
Specic
Thermal
Capacity
J/(kg∙K)
Den-
sity,
kg/m3
Infor-
mation
Source
1. 2. 3. 4. 5. 6.
NatuHemp 95% natural hemp bres, 5%
recycled adhesive binder 0.039 1700 30 [13]
HempFlax
Nature
Insulation
90% hemp bres reinforced
with 10 % Bico or PLA (corn
starch) bre. Soda has been
added as a re deterrent.
0.04 1800 35 [14]
Nature PRO Hemp bres 0.04 n. a. 28 [15]
Thermo-Hemp 82–85% hemp bres,
10–15% bi-component bres,
3–5% sodium bicarbonate 0.038 1600-
2300 30-42 [16, 17]
Thermaeece
Natra Hemp
60% UK grown hemp, 30%
recycled polyester and 10%
polyester binder with a high
recycled content.
0.04 1800 25 [18]
Hemptechnol-
ogy Breathe Hemp 47.5%, ax 47.5%,
polyester 5% 0.039 n. a. 30 [19]
Saint-Gobain
Isover Vegetal
insulation
Hemp and recycled cot-
ton (up to 40%), polyester
binder, phosphate- based re
retardant, treatment to avoid
mould proliferation.
0.039-
0.041 n. a. 35 [20]
Isonat végétal
Hemp bres 42.5%, recycled
cotton 42.5%, textile bres
(recycled polyester) 15% 0.041 n. a. 35 [21]
Fibranatur
Isolant Ouate de
chanvre
90% hemp bres, polyester
binder 0.04 1800 40 [22]
Biob’hemp 90% hemp bres, polyester
binder - natural binder (op-
tional)
0.04 1800 40 [23]
Lenofon Com-
ponents Hemp
Fibre Panel
Mainly hemp bres, a small
proportion of bi-component
bres, and soda for re pro-
tection
0.041 1600 38 [24]
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1. 2. 3. 4. 5. 6.
Technichanvre
hemp wool
TECHNILAINE
85% of hemp bres, 15 % of
stable synthetic binder, non-
emissive
0.04
(0.048
when
wet)
1370 25-30 [25]
STEICO canaf-
lex Hemp bres, ammonium
phosphate, polyolen bres 0.043 1700 40 [26]
Most of the hemp insulating products reviewed are produced from hemp -
bres by adding synthetic or natural binder and additional materials that are needed
to increase the re resistance and, sometimes, mould proliferation. The composition
of hemp insulating materials as well as the whole hemp insulation producers’ mar-
keting strategy shows a clear orientation towards environmentally concerned con-
sumers: some producers provide the opportunity of choosing between polyester and
natural binders, while others stress the fact that recycled materials are used in the
production process.
There are also other properties that are usually mentioned among advantages
of hemp insulation: high acoustic performance; possibility to reuse; low level of
toxins; convenient installation (there are no irritating bres; they are easy to cut);
robustness in handling, transportation, and onsite construction; vapour permeability.
However, there are also some limitations: relatively (in comparison with non-natural
competitors) high price; requirement for thicker walls due to lower thermal conduc-
tivity (in comparison with polystyrene, etc.); application limits due to nishing; nat-
ural insulation is not always produced locally [27]. The last point of limitations is es-
pecially important when environmental impact of an insulating material is assessed.
However, looking to the positive side of this issue, it is possible to argue that wide
spread of local resources as well as positive social impact on the local communities
might be among other advantages of hemp-based insulation.
Coming back to the above mentioned groups of features, it might be con-
cluded that the strongest sides of hemp insulation are related to the environmental
and health-related issues, while physical and economic properties require deeper
analysis in each particular case, when the decision regarding the use of insulation
material is going to be taken.
4. THERMAL CONDUCTIVITY OF HEMP INSULATION PRODUCTS
Among other factors, thermal conductivity plays the central role in the perfor-
mance evaluation of an insulating material. The lower thermal conductivity of the
insulating material, the greater its ability to resist heat transfer and, hence, the greater
is the effectiveness of the insulation. Thermal conductivity is used for calculation of
other common measurements: thermal resistance (R-value) and thermal transmit-
tance (U-value) [28].
The R-value is calculated by the following equation:
λ
l
R=,
(1)
Table 2 continuation
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where λ is the thermal conductivity, and lthe thickness of the material. The U-
value is described as inverse of R-value, thus for monolithic surfaces the former can
be calculated as
l
U
λ
=.
(2)
For multi-layer surfaces, the thermal resistance and the thermal conductivity
of each layer have to be taken into account.
A. The importance of thermal conductivity for economic attractiveness
of insulating material
Despite the fact that external insulation allows full use of the thermal mass and
is the best insulation option [29], there are many cases when exterior insulation is not
feasible. Strict regulations for preservation of the façade of an historic building or dif-
culties in decision-making regarding renovation of a multifamily house are among
good cases in this regard. In such circumstances the insulating materials are used for
insulation of the inner surface of walls. Taking into account that the inner insulation is
sometimes the only option for insulating historic and heritage buildings in old-towns
and other most expensive areas of cities, the worth of area loss can be greater than the
cost of insulation material itself. Thus, thermal conductivity and, respectively, insu-
lation thickness, has a distinctive economic meaning, which might be a serious argu-
ment inuencing the choice of a particular insulation material. This can be illustrated
by the results of hypothetical insulation cost calculations given in Table 3.
In the mentioned table, two cases of insulation are considered, each of them
intentionally not associated with a particular insulation material. The insulation in
the rst case is twice as expensive as that in the second case if only prices per cubic
metre of insulation material are compared. Nevertheless, the thermal conductivity
of insulation used in Case 2 is inferior. The calculations revealed that for the same
U-value of 0.2 it is necessary to use 11.9 cm thick insulation in Case 1 and 15.8 cm
– in Case 2. This increases the relative price of insulation in Case 2, but still remains
lower than that in Case 1. Assuming the real estate price to be 2000 EUR/m2, it can
be found that the cost of space lost in Case 2 compared with Case 1 is worth of
(15.8-11.9)/100∙2000=78 euro per length metre of insulation. Dividing this number
by the ceiling height, we obtain the cost difference of 28.89 euro per square metre
of insulation.
Table 3
Simplied Insulation Cost Calculations*
Case 1 Case 2
1. 2.
Ceiling height ( m) 2.7
U-value before insulation (m2∙K/W) 0.96
Real estate price (EUR/m2) 2000
Thermal conductivity of insulating material
(W/(m∙K)) 0.03 0.04
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1. 2.
Price of insulating material (EUR/m3) 100 50
Insulation thickness required to reach U-value of 0.2
(m2∙K/W), cm 11.9 15.8
Thickness of the nishing (cm)** 1.5 1.5
Total additional thickness (cm) 13.4 17.3
Loss of oor space (m2 per m2 of insulated wall surface) 0.050 0.064
Cost of insulating material (EUR/m2 of insulated wall
surface) 11.88 7.92
Cost of installation and nishing (EUR/m2 of insulated
wall surface) 30.00 30.00
Cost of space lost (EUR/m2 of insulated wall surface) 99.07 128.40
Total cost of insulation (EUR/m2 of insulated wall
surface) 140.95 166.31
* Assumptions are provided in italics.
** It is assumed that nishing has no impact on U-value calculated.
In the example provided in Table 3, the differences in the value of space lost
are the main factor that determines the total cost of insulation, as it accounts for more
than 70% of the total insulation cost in both cases, while the cost of insulating mate-
rial makes only 8.4% in Case 1 and 4.8% in Case 2. Thus, even if only economic
criteria are considered, the price of the insulating material is not necessarily the most
important cost component, and other indirect conductivity-related factors can play
the dominant role.
B. Thermal conductivity of hemp insulation in the context of other insu-
lating materials
The thermal conductivity of commercially available hemp insulation products
under consideration is in the range of 0.038-0.043 W/(m∙K) (see Table 2). This range
is much tighter than can be found in scientic literature, where thermal conductivity
of hemp insulation is reported to be up to 0.094 W/(m∙K) [30]. Comparison of the
thermal conductivity of hemp insulation with that of other insulating materials is
provided in Fig. 2. In this gure, the data about all insulation material types, except
hemp insulation, are based on wide research which covers around eight thousand
thermal conductivity measurements of insulating materials [31].
Table 3 continuation
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Fig. 2. Thermal conductivity of hemp insulation as compared with other insulating materials (infor-
mation source for other materials: [31]).
The thermal conductivity of hemp insulation falls within the ranges of all
generic groups of the insulation and is comparable with those of other brous insula-
tion materials. This is also valid for natural organic insulation, as average thermal
conductivities of cotton, cellulose bres, and sheep-wool insulation are comparable
with the declared values of thermal conductivity of hemp insulation.
C. The thermal conductivity determinants of hemp insulation
The heat can be transferred through an insulation material by combined heat
transfer modes: solid conduction through the solid matrix; natural convection and
gas conduction in the space between bres, and radiation interchanging in participat-
ing media. However, under normal operating conditions, the contribution of natural
convection is negligible [31, 32].
Generally, a relationship exists between the conductivity of an insulating ma-
terial and its density. When the density is low, the conductivity increases with den-
sity decreasing due to high air permeability. Also, a loose structure of bres allows
for heat propagation in the eld of infrared. Thermal conductivity decreases due to
increasing density because of weaker radiation and streaming. However, at high den-
sities the conductivity increases with density due to increasing transmission of heat
in the solid phase by conduction [33]. To put it simpler, in this case the increase in
conductivity is determined by the decrease in the porosity of the insulating material.
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This can be expressed by a polynomial function which consists of the conduc-
tive and radiative members. The conductive member is expressed with the following
equation:
, (3)
where ρ is the density of insulating material.
In turn, the radiative member is expressed as
ρ
λ
c
=
rad
.
(4)
is equation depicts the principle that with the density increasing the more
solid shields that block radiant exchange are found in the structure of insulating
material [31].
e total conductivity is expressed as the sum of (1) and (2):
. (5)
5. RESULTS AND DISCUSSION
The estimation of coefcients for Eq.(5) and for simple linear relationship
(3) was based on the data about commercially available hemp insulation materials
presented in Table 2. However, cases with the density or conductivity ranges only
were excluded in order to avoid sensitivity of the results to subjective choice of a
particular value within the range provided. Thus, the estimation was performed us-
ing 10 observations. The results of estimation are shown in Fig. 3.
Fig. 3. The relationship between the thermal conductivity and the density of hemp insulation
products.
Curves of Fig. 3 generated by Eqs (3) and (5) have relatively low propor-
tions of variance. Moreover, following the interpretation provided by Domínguez-
Muñoz et al. [31], the rst member of Eq.(3) should be the constant conductivity of
air (~0.024 W/(m∙K)). Using the data of commercially available hemp insulation
products, this part of equation could be estimated at the level of 0.0087 W/(m∙K),
which is lower than any corresponding coefcient in [31], i.e. in the range of 0.0146-
0.0385
0.039
0.0395
0.04
0.0405
0.041
0.0415
0.042
0.0425
20 25 30 35 40
Thermal conductivity (W/(m*K))
Density (kg/m
3
)
y=0.0087+0.0005x+0.4477/x, R^2 =0.3519
Declated conductivities
y=0.0365+0.0001x, R^2 =0.2833
λρ
cond ab=+
λρ
ρ
=+ +ab
c
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0.0356 W/(m∙K). For this, there might be several explanations. First, commercial
hemp insulation products have different compositions. Addition of some materials
in order to reduce the re resistance, the choice of binder, and mixing hemp bres
with other insulating materials might have different impacts on the density and ther-
mal conductivity, which will consequently result in a limited t to the equation.
Second, for the analysis the ofcially declared values were used. However, only few
producers provided ofcial certicates. It is possible that some producers measure
only the density (as this requires relatively straightforward procedures), while the
conductivity is based on theoretical assumptions instead of experimental data. Third,
even the density in some cases is provided with quite a wide range and can be not
exact enough: as a natural product, hemp insulation experiences some limitations in
ensuring xed properties. This can be illustrated by the fact that the average declared
density of the hemp insulation material sample analyzed in this research is 34 kg/m3,
while the measured mean density of another sample of ve brous hemp insulation
materials commercially available in the United Kingdom is 50 kg/m3 [34]. Finally,
the experimental investigations sometimes also involve certain methodological as-
pects that limit their comparability with industrial products [35].
The estimation of Eq. (5) shows that the minimum thermal conductivity is
obtained at the hemp insulation density of 29 kg/m3. In principle, this is in line with
the general observation that the lowest conductivities for the majority of insulating
materials are found in the density range of 30-60 kg/m3 [31] as well as with a similar
result (32 kg/m3) obtained for the Purini hemp variety [36].
This result, however, contradicts the data of experimental research [33] that
shows the minimum conductivity being at the density of approx. 77 kg/m3. It might
be good that this difference is caused by fundamentally different compositions of
hemp-based insulation products: the set of commercially available materials of the
type analyzed in this research consist mainly of hemp bres. On the contrary, in
[33] the mixtures including 16-41% hemp chaffs were analyzed. The analysis of
experimental data provided in [33] shows a correlation of 0.49 between the chaff
share and the density, while the correlation between the chaff share and the thermal
conductivity is 0.26.
Another research dealing with similar matter shows that the thermal insu-
lation material where the hemp chaff dominates has a higher thermal conductivity
than hemp bre material. Moreover, densities of materials with considerable share
of hemp chaff are also higher (the density of hemp bre material is reported to be
26 kg/m3, while the densities of the samples where the hemp chaff dominates are in
the range of 132-141 kg/m3) [35]. These trends are also supported by the research
where correlation between thermal conductivity and density of pure hemp chaffs
was analyzed [35]. The experiments were performed in the density range of 92-
108 kg/m3, and it was shown that due to density increase the thermal conductivity
decreases linearly from 0.055 W/(m∙K) to 0.051 W/(m∙K) [37]. Therefore, the use of
hemp chaffs for thermal insulation might be efcient, considering the ratio between
the cost and the thermal properties.
On balance, the results of experimental research works are highly dependent
on the methodology of each experiment; however, the overview of relevant infor-
mation gives some grounds for supposing that inclusion of hemp chaffs into the
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insulation material would: a) increase the density of the material; b) increase the
thermal conductivity; c) shift the “optimal density” (i.e. providing the lowest thermal
conductivity) to the zone of higher densities.
6. CONCLUSIONS
The conclusions based on the results of work are as follows.
Hemp is a multi-purpose plant which can be utilized in different industries.
Possibility to use hemp both for fuel and as feedstock for thermal insulation makes
it a true energy plant. In such usage directions as green energy production and in-
creasing the energy efciency, hemp has a true potential to reduce greenhouse gases
emissions
Currently, considerable proportion of hemp bres is used for production of
insulating materials; however, it is feasible to extend this market not only by increas-
ing the hemp growing and insulation production volumes, but also by developing
new hemp-based insulation products.
The most advantageous features of hemp insulation are related to health and
environmental benets. The orientation towards environmentally cautious consum-
ers is also reected in the marketing strategies of enterprises that produce and sell
hemp-based insulation materials.
Thermal conductivity is one of the most important parameters of any insulat-
ing material. However, its economic interpretation depends on the way the material
is made and on other features, e.g. the price of real estate in the case of inner insula-
tion. The thermal conductivity of commercially available hemp insulation products
is in the range of 0.038-0.043 W/(m∙K) – i.e. falls within the thermal conductivity
ranges of all generic groups of the insulation and is comparable with that of other
brous insulation materials.
Analysis of the thermal conductivity/density ratios has revealed that the mini-
mum declared thermal conductivity is obtained at the declared hemp bres insula-
tion density of 29 kg/m3. Hemp chaffs also have a potential for use as an efcient
thermal insulation, at least considering the relationship between the cost and the
thermal properties.
ACKNOWLEDGEMENT
This work is supported by the ESF “Attraction of Human Resources to Science
(2nd round)” project “Development of the innovative technologies for the accumula-
tion and production of heating and cooling” No 2013/0064/1DP/1.1.1.2.0/13/APIA/
VIAA/050.
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KAŅEPJU SILTUMIZOLĀCIJAS MATERIĀLU ĪPAŠĪBAS
V. Lekavičius1, P. Šipkovs1, S. Ivanovs2, Ā. Ruciņš2
Kopsavilkums
Kaņepes ir daudzfunkcionāls materiāls, kas var tikt izmantots dažādās nozarēs.
Šis pētījums ir vērsts uz iespējām izmantot kaņepju šķiedras izejvielu siltumizolācijas
izstrādājumu ražošanai. Kaņepju šķiedru izolācijas galvenās priekšrocības ir
saistītas ar veselības un vides drošību. Tirgū esošo kaņepju siltumizolācijas produk-
tu siltumvadītspēja tiek salīdzināta ar citu siltumizolācijas materiālu zikālajām
īpašībām. Tirgus izpēte liek secināt, ka jauna tipa kaņepju šķiedru izolāciju materiālu,
kuru izmaksas ir efektīvas, izstrāde ir perspektīvs virziens.
10.12.2014.
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via free access
... industry only uses 16.5% of the yearly hemp straw produced as an insulating material (Lekavicius et al., 2015). ...
... Organic wastes absorb more water than manufactured or synthetic insulation. Hemp, for instance, has a tenfold higher water absorption capacity than polyurethane (Lekavicius et al., 2015). The moisture content of the biomaterials can affect the heat flux, heat capacity, condensation, mold growth, and structural integrity of the insulating panel (Kymäläinen & Pasila, 2000). ...
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